By integrating water meter data recorders as SCADA system
RTUs, Massachusetts Water Resources Authority (MWRA) is making field crews more
efficient and getting indications of problems within seconds.
Previously, information was downloaded from the data recorders
on a weekly basis for monthly customer billing, either manually or via modems.
Both methods were too slow to provide data in a timely manner to field crews or
to give early warnings of problems. Since integrating the data recorders with
our SCADA system, MWRA acquires real-time pressure and flow readings from 150
meters around the greater Boston area every five seconds. This allows field
crews to get data within moments of calling the operations center. Real-time
data also alerts the agency much sooner when there is a problem such as a break in the line.
Customers benefit from the integrated system as well. We
used to compile their usage data monthly so trend data was always “after
the fact.” Now we can show them how much water is used every 30 seconds
over the Web as well as the ability to trend data over the last 24 hours, week,
month, and year. Real-time access to metering information also means that our
field crews stay more productive by providing them with more timely data and we
can detect and fix problems much faster.
MWRA supplies
water to 46 communities in Massachusetts including the city of Boston. The
agency also handles wastewater treatment for many of these communities as well.
MWRA provides between 250 and 350 million gallons of water each day, water that
is consumed by 2.2 million people and 5,500 industrial users.
As a water wholesaler, MWRA’s customers are the water
districts serving Boston and the surrounding communities. MWRA uses an
extensive network of water meters to determine the amount of water entering
each community. Data acquisition devices called Telogers from Telog Instruments
Inc., Victor, N.Y., collect data from the meters. These devices collect meter
data continuously and store the data in fifteen-minute averages in a large,
on-board memory.
Telog was originally chosen in 1989 because they were the
only rugged data acquisition product capable of running on either batteries or
external power. We installed the Telogers during a period of construction when
a lot of manholes had no power.
The first Telog model used by MWRA was a single channel
recorder. It was used to record flow. In those days, field staff went out to
each Teloger on a regular basis and downloaded the information from the
device's memory into a handheld device called a data transfer unit (DTU).
Because the Telog memory was large, it was only necessary to do this about once
a month. That was a major advantage of this system. Usually the batteries
needed recharging before the memory filled up. After the flow data was
downloaded to the handheld unit, it was brought back to the MWRA office,
uploaded to a desktop computer, and used for the flow accounting and revenue
reporting.
In the mid-1990s, the agency upgraded to four-channel
Telogers. The extra channels allowed us to stack differential pressure
transmitters to improve low flow accuracy, collect pressure data and also
monitor what is known as bypass flow — the extremely high flow that
occurs when fire hydrants are opened, for example. Because the new Telogers
were also equipped with modems, MWRA was able to stop manually collecting
metering data at that time. To download data from a particular data logger,
they simply instructed the central computer to dial it up and accessed the
information electronically.
The annual bill and the monthly statements were the only use
of the metering data back when we collected it by hand. Once we started using
modems, the data was also used to support the work of the field crews. In 1996
the MWRA opened its Operational Control Center (OCC). As we built our SCADA
system, our operators used the Telog system to monitor pump station operation
and tank levels. We worked with Telog to develop system “snapshots”
to assist the operators in their system-wide monitoring. The software would
dial up multiple locations and produce a report. The operators, using the Telog
software, could easily produce reports, graphs and dial-up live data.
However, the modem approach was too slow to be truly
useful. When a crew wanted to
perform a repair, they wouldn’t start until they were sure the area they
were working was isolated and water shut down completely. They had to radio
into the OCC where an operator dialed out to the appropriate Teloger to get the
flow and pressure readings. Although this method worked extremely well, it was
somewhat crude. Unfortunately, only one crew could be serviced at one time,
leaving others waiting. It also left us in a vulnerable position in the event
of a break.
By the late
1990s, more changes were coming. The MWRA had migrated out of the DOS
environment and into Windows. We decided to upgrade our data recorders to a
Windows-based product as well. We decided to stick with Telog because their
previous models had served us so reliably. We wanted to take this opportunity
to not only upgrade the existing four-channel Telogs with R-3314 Telogers, but
to bring this valuable meter data into our growing SCADA system.
The first step in this process fell squarely on Telog. They
needed to write a driver that would allow communication over high-speed data
circuits and bring the data into our Intellution HMI package. We then decided
to simplify the replacement process.
A new hardware package (RCU-02) was designed and built by
Telog. This new unit incorporated the Telog 3314 Recorder with modem, a CXR
CSU/DSU, power supply, battery back up, fuse protection and power monitor all
pre-wired to terminal strips. This was all self contained on a 16.5" x
16.5" back plane. All the technicians needed to do was remove the old
recorder, mount the RCU-02 and bring the power, telephone circuits and
transmitter wiring to the terminal strips, thus allowing for a very efficient
installation.
Our new system now gives us the opportunity to utilize a
14-channel recorder with eight analog inputs and six pulse or event inputs.
But that was just the beginning. Our programming staff
developed Graphic User Interface (GUI) screens to allow our operators access to
real-time data at just a click of their mouse. They can also monitor multiple
sites on a single machine, eliminating crews waiting their turn. We can even
set alarms on the fly. Our SCADA system is constantly polling the data
recorders. We can poll all 150 meters in less than five seconds.
We have the ability to configure the SCADA system so that
whenever a data logger shows higher than normal flow or a drop in pressure, we
trigger an alarm. Both those parameters are an indication that something is
wrong, like a break. With this real-time system, we are alerted to a problem
such as that within seconds, instead of minutes, as in the past.
The system is also set up to alert the operator if the data
logger loses AC power. The unit continues to run on batteries, but the alert
allows MWRA to get a technician to the scene before the batteries run down.
MWRA has set up the new system to its customers’
advantage as well. The SCADA system is connected to the MWRA’s data
historian, a program called PI, from Oil Systems. Meter readings are stored in
PI every 30 seconds. This data is then put on MWRA’s special web site.
Our customer community representatives have their own password that allows them
to access their data from the site. It’s almost real time, just 30
seconds old, when we post it to the web. We also give customers access to
software that allows them to do trending and other data analyses.
MWRA has come a long way from the days when its metering
data was used for billing purposes only. We knew that data was an untapped
resource. The key was integrating it with the SCADA system so we could monitor
flow and pressure data in real-time. Now that we can do that, we can supply our
field crews with quick answers to their questions and learn of problems soon
enough to save millions of gallons of water.
